U.S. patent application number 10/807136 was filed with the patent office on 2005-09-29 for frame and method for fabricating the same.
This patent application is currently assigned to ShinMaywa Industries, Ltd.. Invention is credited to Kakimoto, Haruhiko, Tanaka, Yutaka.
Application Number | 20050210820 10/807136 |
Document ID | / |
Family ID | 34988100 |
Filed Date | 2005-09-29 |
United States Patent
Application |
20050210820 |
Kind Code |
A1 |
Tanaka, Yutaka ; et
al. |
September 29, 2005 |
Frame and method for fabricating the same
Abstract
A frame 1 is formed of an outer chord 2 of T-shaped section
having an extension 4 extending inwardly, and an inner chord 3
having a flat portion 5 abutting against the extension 4 of the
outer chord 2. The extension 4 of the outer chord 2 and the flat
portion 5 of the inner chord 3 are friction stir welded together
with one abutted against the other.
Inventors: |
Tanaka, Yutaka; (Hyogo,
JP) ; Kakimoto, Haruhiko; (Hyogo, JP) |
Correspondence
Address: |
NIXON PEABODY, LLP
401 9TH STREET, NW
SUITE 900
WASHINGTON
DC
20004-2128
US
|
Assignee: |
ShinMaywa Industries, Ltd.
Takarazuka-shi
JP
|
Family ID: |
34988100 |
Appl. No.: |
10/807136 |
Filed: |
March 24, 2004 |
Current U.S.
Class: |
52/846 |
Current CPC
Class: |
E04C 3/07 20130101; E04C
3/40 20130101; E04C 2003/0413 20130101; B64C 1/064 20130101; E04C
2003/046 20130101 |
Class at
Publication: |
052/730.6 |
International
Class: |
E04B 007/08; E04C
003/30 |
Claims
What is claimed is:
1. A frame comprising: an outer frame member of T-shaped section
having an extension extending inwardly; and an inner frame member
having a flat portion abutting against the extension of the outer
frame member, wherein the outer frame member and the inner frame
member are friction stir welded together with the edge of the
extension of the outer frame member abutted against the edge of the
flat portion of the inner frame member.
2. The frame of claim 1, wherein the inner frame member is formed
of two or more frame members friction stir welded together with one
abutted against another.
3. A method for fabricating a frame, comprising the steps of:
preparing an outer frame member of T-shaped section having an
extension extending inwardly; preparing an inner frame member
having a flat portion abutting against the extension of the outer
frame member; and friction stir welding the outer frame member and
the inner frame member with the edge of the extension of the outer
frame member abutted against the edge of the flat portion of the
inner frame member.
4. The method for fabricating a frame of claim 3, wherein the step
of preparing an inner frame member comprises the step of friction
stir welding two or more frame members with one abutted against
another.
5. The method for fabricating a frame of claim 3, further
comprising, after friction stir welding the outer frame member and
the inner frame member, the step of subjecting the outer and inner
frame members together to surface treatment or finish coating.
6. The method for fabricating a frame of claim 4, further
comprising, after friction stir welding the outer frame member and
the inner frame member, the step of subjecting the outer and inner
frame members together to surface treatment or finish coating.
Description
BACKGROUND OF THE INVENTION
[0001] (a) Field of the Invention
[0002] This invention relates to frames and methods for fabricating
the same.
[0003] (b) Description of the Related Art
[0004] For structures required to have both light weight and
rigidity, such as airplane bodies and wings, so-called monocoque
construction or semi-monocoque construction are traditionally
employed (see, for example, Japanese Unexamined Patent Publication
No. 5-286496). Monocoque construction is formed of a plurality of
ring-like frames and an outer panel that covers these frames so
that the outer panel, having a small rigidity in itself, is
reinforced by the frames, thereby implementing a light-weight and
rigid structure. In semi-monocoque construction, as shown in FIG.
8, an outer panel 101 is provided with not only frames 102 but also
stringers 103 that extend in the longitudinal direction of the body
and intersect with the frames 102. Semi-monocoque construction thus
implements a more rigid structure by both the frames 102 and the
stringers 103.
[0005] As shown in FIGS. 9A and 9B, the conventional frame 102 is
formed of an outer chord 105 of T-shaped section, a web 106 like a
flat plate, and an inner chord 107 of L-shaped section, which are
joined together by a large number of fasteners 108. The
conventional frame 102 is fabricated in the following manner.
[0006] First, as shown in steps S101, S201 and S301 in FIG. 10, an
outer chord 105, a web 106 and an inner chord 107 are fabricated in
separate steps, subjected individually to surface treatment (see
steps S102, S202 and S302), and subjected individually to finish
coating (see steps S103, S203 and S303). Then, these members are
assembled (see step S104). In assembly, an extension of the outer
chord 105 and the web 106 are overlapped, and then fastened along
their rims by a large number of fasteners 108. Similarly, the web
106 and the inner chord 107 are also overlapped and fastened along
their rims by a large number of fasteners 108. The conventional
frame 102 is fabricated in this manner.
[0007] As described above, the conventional frame 102 requires many
fasteners 108 for the joining between the outer chord 105 and the
web 106 and for the joining between the web 106 and the inner chord
107. Therefore, the weight of the frame 102 is increased by those
of the fasteners 108. Furthermore, the joinings using the fasteners
108 involve the provision of the overlapping portions of the outer
chord 105, the web 106 and the inner chord 107. Therefore, the
weight of the frame 102 is also increased by those of the
overlapping portions.
[0008] Furthermore, the surface treatment process (see steps S102,
S202 and S302) and the finish coating process (see steps S103, S203
and S303) are necessary for each of the outer chord 105, the web
106 and the inner chord 107. This increases the number of process
steps, leading to much expense in time and cost. Furthermore, the
surface treatment and finish coating processes necessary as a
preliminary stage for the assembly process must be carried out for
each of the outer chord 105, the web 106 and the inner chord 107.
This invites an elongated lead time.
SUMMARY OF THE INVENTION
[0009] The present invention has been made in view of the foregoing
points, and therefore its object is to provide a frame light in
weight and small in the number of process steps and a method for
fabricating the same.
[0010] In a first aspect of the invention, a frame comprises: an
outer frame member of T-shaped section having an extension
extending inwardly; and an inner frame member having a flat portion
abutting against the extension of the outer frame member, wherein
the outer frame member and the inner frame member are friction stir
welded together with the edge of the extension of the outer frame
member abutted against the edge of the flat portion of the inner
frame member.
[0011] In a second aspect of the invention, the frame according to
the first aspect is characterized in that the inner frame member is
formed of two or more frame members friction stir welded together
with one abutted against another.
[0012] In a third aspect of the invention, a method for fabricating
a frame comprises the steps of: preparing an outer frame member of
T-shaped section having an extension extending inwardly; preparing
an inner frame member having a flat portion abutting against the
extension of the outer frame member; and friction stir welding the
outer frame member and the inner frame member with the edge of the
extension of the outer frame member abutted against the edge of the
flat portion of the inner frame member.
[0013] In a fourth aspect of the invention, the method according to
the third aspect is characterized in that the step of preparing an
inner frame member comprises the step of friction stir welding two
or more frame members with one abutted against another.
[0014] In a fifth aspect of the invention, the method according to
the third or fourth aspect is characterized by further comprising,
after friction stir welding the outer frame member and the inner
frame member, the step of subjecting the outer and inner frame
members together to surface treatment or finish coating.
[0015] According to the first and third aspects of the invention,
the inner and outer frame members are joined together by friction
stir welding, and therefore no fasteners are needed for the
joining. As a result, the frame can be reduced in weight by the
weight corresponding to fasteners that would conventionally be
required. Furthermore, since the inner and outer frame members are
joined together with one abutted against the other, no overlapping
portion between both the members is needed. Therefore, the frame of
the invention can have a smaller weight than the conventional frame
by the weight corresponding to the overlapping portions.
[0016] According to the second and fourth aspects of the invention,
the inner frame member is formed by butting two or more frame
members together. Therefore, the frame diametral dimension (or
lateral width) can be increased. Since the frame members
constituting the inner frame member are friction stir welded
together with one abutted against another, there is no need for
fasteners for the joining of them and also no need for their
overlapping portions. Therefore, the inner frame member can be
reduced in weight.
[0017] According to the fifth aspect of the invention, the inner
and outer frame members need not be subjected individually to
surface treatment or finish coating. Therefore, the number of
process steps and the lead time can be reduced.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a perspective view of a frame.
[0019] FIG. 2 is a flow chart of a method for fabricating a
frame.
[0020] FIG. 3A is a perspective view showing an extrusion for an
outer chord.
[0021] FIG. 3B is a perspective view showing an outer chord.
[0022] FIG. 4A is a perspective view showing an extrusion for an
inner chord.
[0023] FIG. 4B is a perspective view showing an inner chord.
[0024] FIG. 5 is a perspective view of another frame.
[0025] FIG. 6 is a perspective view of still another frame.
[0026] FIG. 7 is a flow chart of another method for fabricating a
frame.
[0027] FIG. 8 is a perspective view of a body.
[0028] FIG. 9A is a perspective view of a conventional frame.
[0029] FIG. 9B is a cross-sectional view of the conventional
frame.
[0030] FIG. 10 is a flow chart showing a method for fabricating a
conventional frame.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] Hereinafter, description will be made of embodiments of the
present invention with reference to the drawings.
[0032] A frame 1 according to this embodiment is used as a frame in
an airplane body of monocoque or semi-monocoque construction. The
entire structure of the monocoque or semi-monocoque body is well
known, and therefore explanation thereof is not given herein (see
FIG. 8).
[0033] FIG. 1 shows the structure of the frame 1. The frame 1 is
formed of an outer chord 2 of T-shaped section having an extension
4 extending inwardly, and an inner chord 3 of L-shaped section
having a flat portion 5. In this embodiment, the outer chord 2 and
the inner chord 3 are made from aluminum. The outer chord 2 and the
inner chord 3 are formed to have an elongate shape, and are curved
along the inner periphery of the airplane body. In this embodiment,
the inner edge of the outer chord 2 and the outer edge of the inner
chord 3 have the same curvature. The outer chord 2 and the inner
chord 3 are friction stir welded together with the edge of the
extension 4 abutted against the edge of the flat portion 5. The
extension 4 and the flat portion 5 are welded continuously on their
seam, whereby the frame 1 are formed with a joint 6 extending along
its curvature.
[0034] In the case of a semi-monocoque body, the frames intersect
with stringers and an outer panel is provided on the body surface
sides of these members. The frame and the stringer are equal in
that they act as reinforcing members. Both the members, however,
are different in that the stringer is a member extending along the
longitudinal direction of the body, while the frame is a member
orthogonal to the longitudinal direction of the body and extending
along the inner periphery of the body. By reason of this
difference, the frame is actually designed and fabricated from a
different view point from the fabrication of the stringer.
[0035] Next, a fabrication method for the frame 1 will be described
with reference to the flow chart of FIG. 2. First, in step S1, a
straight extrusion 10 (see FIG. 3A) of T-shaped section is
fabricated by extruding or drawing. Then, in step S2, the extrusion
10 is bent by stretch forming. In this manner, an outer chord 2
(see FIG. 3B) is prepared from the extrusion 10. Thereafter, heat
treatment is conducted on the prepared outer chord 2 as necessary
to complete the outer chord 2 (see step S3). It is needless to say
that instead of fabricating an extrusion 10, a standard extrusion
can be purchased and an outer chord 2 can be prepared from the
purchased extrusion.
[0036] For the preparation of an inner chord 3, a straight
extrusion 11 (see FIG. 4A) of L-shaped section is first fabricated
by extruding or drawing in step S4. Then, in step S5, the extrusion
11 is bent by stretch forming. In this manner, an inner chord 3
(see FIG. 4B) is prepared from the extrusion 11. Thereafter, heat
treatment is conducted on the prepared inner chord 3 as necessary
to complete the inner chord 3 (see step S6). Also for the inner
chord 3, it is needless to say that instead of fabricating an
extrusion 11, a standard extrusion can be purchased and an inner
chord 3 can be prepared from the purchased extrusion.
[0037] The fabrication process for an outer chord 2 in steps S1 to
S3 and the fabrication process for an inner chord 3 in steps S4 to
S6 are individually conducted. Therefore, both the fabrication
processes may be carried out concurrently or one after the
other.
[0038] Next, in step S7, the completed outer chord 2 and inner
chord 3 are friction stir welded together with the extension 4 of
the outer chord 4 abutted against the flat portion 5 of the inner
chord 3. In this embodiment, the outer chord 2 and the inner chord
3 are welded continuously to draw a curve on their seam. However,
there is no particular limit to welding points of the friction stir
welding. For example, both the chords may be welded at discrete
points on the seam, or may be welded discontinuously to draw a
dotted curve.
[0039] After the outer and inner chords 2 and 3 are joined
together, the process proceeds with step S8 in which the outer and
inner chords 2 and 3 are together subjected to surface treatment.
In this case, anodizing is conducted as surface treatment to form a
coating on the surface of the frame 1. Thereafter, the outer and
inner chords 2 and 3 are together subjected to finish coating in
step S9, thereby completing the frame 1 (step S10).
[0040] For the purpose of weight reduction of the frame 1, as shown
in FIG. 5, the flange 9 may be formed with cutaways (flange trims)
7 or holes (not shown). Alternatively or additionally, the flat
portion (web) 5 may be formed with holes 8. In these cases, the
formation of cutaways or holes is carried out after the friction
stir welding in step S7.
[0041] As can be seen from the discussion above, the frame 1
according to this embodiment can be reduced in weight because of
the absence of fasteners. Furthermore, the outer and inner chords 2
and 3 are joined with one abutted against the other, and therefore
they need not be overlapped with each other. As a result, the frame
1 of this embodiment can have a smaller weight than the
conventional frame by the weight corresponding to the overlapping
portions.
[0042] The joining of the outer and inner chords 2 and 3 is made by
friction stir welding. Therefore, both the members 2 and 3 can be
joined with increased ease and reliability as compared with the
joining using fasteners.
[0043] Each of surface treatment and finish coating can be
conducted on the outer and inner chords 2 and 3 at one time after
the joining of them, and need not be conducted on each of them.
Therefore, the number of process steps for the outer and inner
chords 2 and 3 can be extensively reduced. This results in
shortened lead time.
[0044] Next, as a modification, description will be made of a frame
15 formed of an outer chord 2, an inner chord 3 and a web 12 like a
flat plate with reference to FIG. 6. This frame 15 includes the web
12 between the outer chord 2 and the inner chord 3, so that the
frame diametral dimension (or the flame lateral width) is
increased. The outer chord 2, the inner chord 3 and the web 12 are
all made of aluminum. In this modification, the outer chord 2
constitutes an outer frame member, while the inner chord 3 and the
web 12 constitute an inner frame member.
[0045] FIG. 7 shows a flow chart of a method for fabricating a
frame 15. In this method, the outer and inner chords 2 and 3 are
fabricated in the same manner as described above (see steps S1 to
S3 and S4 to S6). On the other hand, as shown in steps S11 and S12,
the web 12 is formed by cutting a flat plate (sheet metal) of
aluminum into a predetermined shape. Thereafter, the outer chord 2
and the web 12 are friction stir welded together with the extension
4 of the outer chord 2 abutted against one edge of the web 12, and
the web 12 and the inner chord 3 are also friction stir welded
together with the other edge of the web 12 abutted against one edge
of the inner chord 3 (step S7). Then, the welded outer chord 2, web
12 and inner chord 3 are together subjected to surface treatment
(step S8) and then finish coating (step S9), thereby implementing a
frame 15.
[0046] Therefore, the foregoing various effects can also be
achieved according to the frame 15 and its fabrication method.
[0047] The number of webs 12 provided is not restricted to one. If
necessary, two or more webs can be abutted and friction stir welded
together to further increase the frame diametral dimension.
[0048] The material for the frames 1 and 15 is not restrictive, and
metals other than aluminum can be used for the frames 1 and 15.
[0049] The frames 1 and 15 are not used only for airplane bodies,
but may be used for the other parts (for example, wings).
Furthermore, the applications of the frame according to the present
invention include not only airplanes but also ships, vessels,
vehicles and other structures such as buildings.
[0050] The frames 1 and 15 are not restrictive in their shape, but
can take various shapes. For example, the frames 1 and 15 may have
a bent shape or a linear shape.
* * * * *